bpo-40939: Remove the old parser (GH-20768)

This commit removes the old parser, the deprecated parser module, the old parser compatibility flags and environment variables and all associated support code and documentation.

Parser/peg_api.c

@@ -0,0 +1,54 @@
+#include "pegen_interface.h"
+
+#include "tokenizer.h"
+#include "pegen.h"
+
+mod_ty
+PyPegen_ASTFromString(const char *str, const char *filename, int mode,
+                      PyCompilerFlags *flags, PyArena *arena)
+{
+    PyObject *filename_ob = PyUnicode_FromString(filename);
+    if (filename_ob == NULL) {
+        return NULL;
+    }
+    mod_ty result = PyPegen_ASTFromStringObject(str, filename_ob, mode, flags, arena);
+    Py_XDECREF(filename_ob);
+    return result;
+}
+
+mod_ty
+PyPegen_ASTFromStringObject(const char *str, PyObject* filename, int mode,
+                            PyCompilerFlags *flags, PyArena *arena)
+{
+    if (PySys_Audit("compile", "yO", str, filename) < 0) {
+        return NULL;
+    }
+
+    mod_ty result = _PyPegen_run_parser_from_string(str, mode, filename, flags, arena);
+    return result;
+}
+
+mod_ty
+PyPegen_ASTFromFilename(const char *filename, int mode, PyCompilerFlags *flags, PyArena *arena)
+{
+    PyObject *filename_ob = PyUnicode_FromString(filename);
+    if (filename_ob == NULL) {
+        return NULL;
+    }
+
+    mod_ty result = _PyPegen_run_parser_from_file(filename, mode, filename_ob, flags, arena);
+    Py_XDECREF(filename_ob);
+    return result;
+}
+
+mod_ty
+PyPegen_ASTFromFileObject(FILE *fp, PyObject *filename_ob, int mode,
+                          const char *enc, const char *ps1, const char* ps2,
+                          PyCompilerFlags *flags, int *errcode, PyArena *arena)
+{
+    if (PySys_Audit("compile", "OO", Py_None, filename_ob) < 0) {
+        return NULL;
+    }
+    return _PyPegen_run_parser_from_file_pointer(fp, mode, filename_ob, enc, ps1, ps2,
+                                        flags, errcode, arena);
+}